US 2014/0288801 A1 has disclosed a generic cooling system of a motor vehicle, having an exhaust-gas recirculation arrangement and having an exhaust-gas recirculation cooler integrated into the exhaust-gas recirculation arrangement.
A generic cooling system of a motor vehicle is also known from JP 2008-261297 A. In general, cooling components, such as in particular exhaust-gas coolers manufactured from high-grade steel, which are incorporated into a coolant circuit of a motor vehicle have a relatively high replacement value. This is based not only on the high material costs but also on likewise high manufacturing costs. For this purpose, it is desirable for such cooling components to be effectively protected against damage, even if, as a result of faults in the motor vehicle, they are operated not in the intended manner. Here, in particular in the case of an exhaust-gas recirculation cooler, there is a high risk of damage if a fault occurs in the coolant circuit. This may be caused for example by faults in the actuation arrangement, or failures of valves or pumps, or else as a result of selection of, or damage to, relatively inexpensive components in the line system, such as hoses, clamps, screw connections or the like. Here, exhaust-gas recirculation coolers are at particular risk because they exhibit relatively high power and simultaneously relatively low thermal inertia, and, for example in the event of a fault in the coolant circuit, heat up within a few seconds to such an extent that they can sustain damage. Even if it is the case here that the engine switches over very quickly into an emergency running mode, for example associated with a power reduction, it cannot be ensured that the exhaust-gas cooler remains undamaged. Special protection of the exhaust-gas recirculation cooler has therefore hitherto not been provided at all.